Mechanism for simultaneously cutting tensioned bobbin threads as all the needle heads of an automatic embroidering machine

ABSTRACT

A mechanism for simultaneously cutting tensioned bobbin threads at all the needle heads of an automatic embroidering machine comprises a reciprocable draw bar which extends below all the needle heads. A cutter blade is provided under each needle head and is secured to the draw bar so as to be operable by the displacement of said draw bar. A fixed counterblade is associated with and located in spaced relationship to each cutter blade. A thread drawing lever is arranged to be operable by the draw bar at the same time as the cutter blade, for cooperation with a thread clamp fixedly mounted in spaced relationship to the thread drawing lever, said counterblade being located alongside the deflection path of said thread drawing lever.

United States Patent [1 1 Trageser Sept. 25, 1973 [76] Inventor: Ludwig Trageser, 32 Von Bargen Strasse, Hamburg, Germany [22] Filed: May 5, 1972 [21] Appl. No.: 252,142

[30] Foreign Application Priority Data 2,707,927 5/1955 Artzt et a1 112/252 2,968,269 1/1961 Smith et a1..... 112/253 X 3,371,633 3/1968 Hedgegaard... 112/252 3,559,603 2/1971 Littell 112/252 Primary Examiner-Werner H. Schroeder Att0rney-Neil F. Markva et al.

[5 7] ABSTRACT A mechanism for simultaneously cutting tensioned bobbin threads at all the needle heads of an automatic embroidering machine comprises a reciprocable draw sept' 1971 Germany P 71 34 050'6 bar which extends below all the needle heads. A cutter blade is provided under each needle head and is se- }J.S. Cl 112/252, 112/155, 112/253 cured to the draw bar so as to be Operable by the nt. Cl D05b 65/00 f 58 Field of Search 112/2 78 79 R P1a?emem 9 draw 5 soclated with and located in spaced relationship to 112/117, 122, 123, 130, 155,163, 252, 253,

266 each cutter blade. A thread drawing lever 1s arranged to be operable by the draw bar at the same time as the cutter blade, for cooperation with a thread clamp [56] References Clted fixedly mounted in spaced relationship to the thread UNITED STATES PATENTS drawing lever, said counterblade being located along- 3,391,665 7/1968 Kozuka 112/252 ide the deflection path of said thread drawing lever. 2,846,967 8/1958 Doerr et a1. 2,682,841 7/1954 McCutchen 112/79 R 10 Claims, 5 Drawing Figures F- r l J o 8 o I I/ I 1 MECHANISM FOR SIMULTANEOUSLY CUTTING TENSIONED BOBBIN THREADS As ALL THE NEEDLE HEADS or AN AUTOMATIC EMBROIDERINC MACHINE BACKGROUND OF THE INVENTION This invention relates to a mechanism for simultaneously cutting tensioned bobbin threads at all the needle .heads of an automatic embroideringv machine.

When the color of the bobbin thread or a frame is changed, or when the end of an embroidery motif has been reached, the bobbin threads at the needle heads of an automatic embroidering machine are cut by a thread cutter.

Hitherto this was done after the work had been clamped up by pulling the bobbin thread at each needle head up with the aid of the needle thread and wedging the bobbin thread between clamping discs. The cutting off of unwanted thread ends shortly after stitching had begun necessitated another stoppage of the automatic embroidering machine. At the end of the embroidery motif the work had to be released and drawn off together with the bobbin thread before the latter could be cut with a pair of ordinary scissors. This procedure is particularly tedious when producing trimming embroidery on an automatic embroidering machine having several needle heads.

SUMMARY OF THE INVENTION It is the object of the invention to overcome these drawbacks and to provide a simple and reliable mechanism for simultaneously cutting the bobbin thread at every needle head of an automatic embroidering machine.

Another object of the invention is so to contrive the said mechanism that it is functionally foolproof and requires no maintenance.

To attain these objects the present invention provides a mechanism for simultaneously cutting tensioned bobbin threads at all the needle heads of an automatic embroidering machine, which comprises a reciprocable draw bar extending below all the needle heads; a cutter blade provided under each needle head and secured to the draw bar so as to be operable by the displacement of said draw bar; a fixed counterblade associated with and located in spaced relationship to each cutter blade, and a thread drawing lever arranged to be operable by the draw bar at the same time as the cutter blade, for cooperation with a thread clamp fixedly mounted in spaced relationship to the thread drawing lever, said counterblade being located alongside the deflection path of said thread drawing lever.

In a very convenient manner the proposed cutting mechanism enables the bobbin threads at all the needle heads to be cut by a single movement of the draw bar and the cut thread ends to be held. A fresh part of the embroidery can be started without the necessity of the bobbin threads being pulled upwards and without the risk of the long thread ends forming knots and loops on the back of the embroidered article.

In a useful development of the proposed mechanism, the cutter blade may be deflectable about a pivot pin affixed to the stitch plate of the automatic embroidering machine and operable by a pin on the draw bar adapted slidably to engage a longitudinal slot in the cutter blade, in such a manner that when operated the cutter blade will swing across the counterblade with a shearing action.

According to another feature of the invention the thread drawing lever, by virtue of a pin on the draw bar slidably engaging a longitudinal slot in the thread draw ing lever may be positively operable by the draw bar to swing towards the thread clamp about a fixed pivot pin.

Moreover, the invention also proposes to attach the counterblade to an upper stitch plate alongside the deflection path of the thread drawing lever between the latter and the thread clamp. In such an arrangement the thread drawing lever and the cutter blades are readily accessible after the removal of the stitch plate.

Furthermore, as proposed by the invention a thread deflector may be affixed to the stitch plate below the cutter blade to prevent the loops formed by the thread below the stitch plate from snarling and causing the thread to break.

BRIEF DESCRIPTION OF THE DRAWING Two embodiments of the invention will now be described by way of example and with reference to the accompanying drawing, in which:

FIG. 1 is a schematic view from above of an automatic embroidering machine according to the invention, which is fitted with several needle heads and an automatic setting mechanism, the drawing being in two parts divided at I I;

, FIG. 2 is a view from above of the disposition of a cutter blade associated with a thread drawing lever and a thread clamp below one of the needle heads;

FIG. 3 is a front elevation of FIG. 2;

FIG. 4 is another embodiment of the cutter blade, and

FIG. 5 is a front elevation of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the mechanism for cutting the bobbin threads according to the invention is shown in FIGS. 1 to 3 and comprises a draw bar 2 extending under the needle heads 1 across the full length of an automatic embroidering machine 15 and, below each needle head 1, a cutter blade 3 cooperating with a counterblade 4. For tensioning the bobbin thread a thread drawing lever 5 and a thread clamp 6 are also provided. The draw bar 2 is covered above by a plate which contains an opening under each needle head 1 below which the parts for cutting the bobbin threads are arranged. A stitch plate 10 closes the opening in the plate and covers all the members of the mechanism. The stitch plate 10 is made of a transparent material.

At each needle head 1 the draw bar 2 slides in a bearing 16. Each cutter blade 3 (FIG. 2) is secured to the draw bar 2 by a screw 17, its free end projecting from the draw bar 2 to a guideway 11.

Below the cutter blade 3 a guard plate 12 is affixed to the draw bar 2 to prevent the loop which the thread forms at every stitch from snarling up under the stitch plate 10 and breaking.

For cutting a bobbin thread the cutter blade 3 (FIG. 2) moves in the arrowed direction 18 towards the counterblade 4 which is affixed to the stitch plate 10 and the cutter blade 3 slides directly under the counterblade 4 with a scissor blade action.

In a different embodiment of the proposed mechanism shown in FIGS. 4 and 5, a cutter blade 27 is horizontally deflectably fulcrumed on the stitch plate by a pivot pin 28. A pin 29 affixed to the draw bar 2 slidably engages a longitudinal slot 30 in the cutter blade 27 so that, when the draw bar 2 is moved in the arrowed direction 18 the cutter blade 27 will perform a scissor blade movement towards the counterblade 4. In position of rest the deflectable end of the cutter blade 27 overrides a thread deflector 31 which is affixed to the stitch plate 10. The thread deflector 31 is intended to prevent the loops which the thread forms at each stitch below the stitch plate 10 from snarling and causing the thread to break.

Provided in the stitch plate recess of each needle head 1 is a thread drawing lever 5 which, by virtue of a pin 8 affixed to the draw bar 2 sliding in a longitudinal slot 9 in the thread drawing lever 5, performs a positively controlled swinging movement about a fixed pivot pin 7 in relation to a thread clamp 6. For engaging the bobbin thread the thread drawing lever 5 is provided with a notch at its deflectable end. When in inactive position, as shown in FIGS. 2 and 4, the thread drawing lever 5 is located directly adjacent the outlet hole 19 for the bobbin thread and the counterblade 4 is located between the thread drawing lever 5 and the thread clamp 6 directly in the path 20 of the bobbin thread. For tensioning the bobbin thread the thread drawing lever 5 swings in a plane under the counterblade 4.

During normal stitch formation the individual bobbin thread cutters with their associated needle heads 1 are in position of rest.

For initiating the operation of cutting the bobbin threads the draw bar 2 is actuated by a shift lever 21 which during the stitching action is locked by a locking slide 22 associated with a locking lever 23 and a cam disc 24. The cam disc 24 is mounted on the looper drive shaft and works at about 350 rpm. The cam disc 24 maintains the locking lever 23 in an oscillating to and fro motion and at the end of each revolution of the cam disc 24 it briefly releases the locking slide 22 and hence the shift lever 21. The shift lever 21 is released only at the instant the needles of the needle heads 1 of the automatic embroidering machine 15 are at top dead center. The rapidity of reciprocation of the lock ing lever 23 prevents the shift lever 21 from being actuated or released during the stitching action (i.e., when the automatic embroidering machine runs).

However, when a color change is required or at the end of a motif the automatic embroidering machine 15 automatically stops at top dead center of the needles. in this position the shift lever 21 is free and the draw bar 2 can be moved in the arrowed direction 18 for cutting the threads. Before the cutter blade 3 and the counterblade 4 close with a scissor blade action and cut the bobbin thread, the notch in the free end of the thread drawing lever 5 reaches the thread clamp 6 and pushes the bobbin thread into the wedge 25 of the thread clamp. Not until this has occurred is the bobbin thread cut. The end of the thread from the bobbin is safely held in the thread clamp 6 until stitching is resumed.

A break switch 26 prevents the automatic embroidering machine 15 from being started whilst the cutter blades 3 are still being operated by the shift lever 21. The break switch 26 interrupts the starting circuit of the motor driving the automatic embroidering machine.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments are therefore to be considered in all respects as illustrative and not restrictive.

What is claimed is:

1. A mechanism for simultaneously cutting a plurality of tensioned bobbin threads adjacent a plurality of needle heads of an automatic embroidering machine, comprising a. a fixed counterblade adjacent each needle head,

b. a plurality of thread drawing levers, each mounted at each of said heads for movement along a path past said counterblade for drawing a thread over said counterblade,

c. a plurality of fixed thread clamps, each located at each of said heads at one end of the path of a drawing lever for receiving and retaining said thread drawn by said drawing lever,

d. a plurality of cutter blades each mounted at each of said heads for movement along a further path to cooperate with each said counterblade and sever said drawn thread, and

e. means for simultaneously moving both said thread drawing levers and said cutter blades along their respective paths such that said thread drawing lever first draws the thread over said counterblade which thread is secured by said thread clamp before said cutter blade cooperates with said counterblade to sever said thread.

2. A mechanism according to claim 1 further comprising thread guide means located on the side of said counterblade opposite said thread clamp and in a plane defined by said counterblade and thread clamp whereby said thread is maintained over said counterblade as it is drawn by said drawing lever towards and into engagement with said thread clamp.

3. A mechanism according to claim 2 wherein said moving means comprises a reciprocably mounted draw bar extending adjacent all of said needle heads for simultaneously moving both said thread drawing levers and said cutter blades.

4. A mechanism according to claim 3 wherein each of said thread drawing levers is pivotally mounted and includes a longitudinal slot therein, and a plurality of pins are mounted in spaced relationship along said draw bar, each pin extending through one of said slots, whereby upon movement of said draw bar each of said drawing levers swings towards the respective thread clamp drawing each thread across one of said counterblades to be secured by one of said thread clamps.

5. A mechanism according to claim 4 wherein each of said cutter blades is pivotally mounted and includes a longitudinal slot therein and a plurality of pins are mounted in spaced relationship along said draw bar, each pin extending through one of said slots whereby upon movement of said draw bar each of said cutter blades swings across its respective counter-blade with a shearing action.

6. A mechanism according to claim 4 wherein each of said cutter blades is fixedly secured to said draw bar whereby upon movement of said draw bar each of said cutter blades moves across its respective counterblade with a shearing action.

7. A mechanism according to claim 6 wherein one end of each of said cutter blades is secured to said draw bar, said mechanism further comprising guide means 9. A mechanism according to claim 8 wherein said locking means is adapted to release said moving means only when operation of said machine is terminated with said needle heads in a predetermined position.

10. A mechanism according to claim 9 further comprising means for preventing operation of said machine except when said draw bar is in a predetermined position whereby said machine cannot be operated simultaneously with movement of said draw bar.

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1. A mechanism for simultaneously cutting a plurality of tensioned bobbin threads adjacent a plurality of needle heads of an automatic embroidering machine, comprising a. a fixed counterblade adjacent each needle head, b. a plurality of thread drawing levers, each mounted at each of said heads for movement along a path past said counterblade for drawing a thread over said counterblade, c. a plurality of fixed thread clamps, each located at each of said heads at one end of the path of a drawing lever for receiving and retaining said thread drawn by said drawing lever, d. a plurality of cutter blades each mounted at each of said heads for movemEnt along a further path to cooperate with each said counterblade and sever said drawn thread, and e. means for simultaneously moving both said thread drawing levers and said cutter blades along their respective paths such that said thread drawing lever first draws the thread over said counterblade which thread is secured by said thread clamp before said cutter blade cooperates with said counterblade to sever said thread.
 2. A mechanism according to claim 1 further comprising thread guide means located on the side of said counterblade opposite said thread clamp and in a plane defined by said counterblade and thread clamp whereby said thread is maintained over said counterblade as it is drawn by said drawing lever towards and into engagement with said thread clamp.
 3. A mechanism according to claim 2 wherein said moving means comprises a reciprocably mounted draw bar extending adjacent all of said needle heads for simultaneously moving both said thread drawing levers and said cutter blades.
 4. A mechanism according to claim 3 wherein each of said thread drawing levers is pivotally mounted and includes a longitudinal slot therein, and a plurality of pins are mounted in spaced relationship along said draw bar, each pin extending through one of said slots, whereby upon movement of said draw bar each of said drawing levers swings towards the respective thread clamp drawing each thread across one of said counterblades to be secured by one of said thread clamps.
 5. A mechanism according to claim 4 wherein each of said cutter blades is pivotally mounted and includes a longitudinal slot therein and a plurality of pins are mounted in spaced relationship along said draw bar, each pin extending through one of said slots whereby upon movement of said draw bar each of said cutter blades swings across its respective counter-blade with a shearing action.
 6. A mechanism according to claim 4 wherein each of said cutter blades is fixedly secured to said draw bar whereby upon movement of said draw bar each of said cutter blades moves across its respective counter-blade with a shearing action.
 7. A mechanism according to claim 6 wherein one end of each of said cutter blades is secured to said draw bar, said mechanism further comprising guide means for simultaneously guiding the opposite ends of all of said cutter blades during movement of said draw bar and cutter blades.
 8. A mechanism according to claim 1 further comprising means locking said means for simultaneously moving both said thread drawing levers and said cutter blades against movement during operation of said automatic embroidering machine and for automatically releasing said moving means upon termination of operation of said machine.
 9. A mechanism according to claim 8 wherein said locking means is adapted to release said moving means only when operation of said machine is terminated with said needle heads in a predetermined position.
 10. A mechanism according to claim 9 further comprising means for preventing operation of said machine except when said draw bar is in a predetermined position whereby said machine cannot be operated simultaneously with movement of said draw bar. 